The police sergeant said he believed he was in danger and that the teenager was armed, but a weapon was never recovered.

A home surveillance camera captured the violent encounter in front of a home near 111th Street and Hermosa Avenue on August 13, 2017. Then 18-year-old Ricardo Hayes had been running and then stopped in front of the home.

The video shows off-duty Sergeant Khalil Muhammad pulling up in his personal pickup truck. Seconds went by, then when Hayes slowly moved toward Muhammad, the sergeant fired shots, wounding Hayes in the chest and arm.

Muhammad called 911. In the background of the call Hayes can be heard screaming.

"I'm behind Morgan Park High School. I'm a (inaudible) sergeant of police. I need an ambulance right now," Muhammad says on the 911 call recording.

"What happened?" the operator asks.

"The guy pulled like he was about to pull a gun on me, walked up to the car, and I had to shoot," Muhammad answers.

Hayes survived the shooting and has now filed a lawsuit. Hayes' attorney, Gabriel Hardy, said his client has developmental disabilities and problems communicating.